1. Field of the Invention
The invention relates generally to expansion joint fire barrier systems and, more particularly, but not by way of limitation it relates to an improved system that utilizes a combination of thin, relatively flexible stainless steel sheets with a fire resistant fiber composition in particularly folded and reinforced configuration, such barrier combinations being capable of installation in selected multiples at an expansion joint assembly.
2. Description of the Prior Art
The prior art includes several types of attempt at providing fire or smoke barriers across expansion joints, and some of these prior designs have been used in combination with forms of expansible joint. The U.S. Pat. No 4,517,779 in the name of Dunsworth, property of the present assignee, best characterizes the present state of the art as regards expansible fire barrier structure. This patent teaches an expansion joint assembly which includes a barrier box containing fire resistant, moisturized material, and the assembly is also utilized with an underlying expansible fire and smoke barrier comprised of METAFLEX.RTM., a coated silica fabric. Multi-foil type thermal insulation materials have also been utilized in the past in such as radio-isotope power systems. Aluminum, copper and nickel foil radiation shields have been utilized in combination with fibrous spacers in the form of plain and metal-flake opacified papers with woven fabrics selected to separate the separate radiation shields. Foil thermal radiation shields of brass, chromium, silver and gold have also been explored with varying success.
More particular to the area of building materials, a relatively thin, flexible sheeting has been constructed containing sodium silicate, glass fiber and a wire netting core. The sheeting is then coated on both sides with an epoxy resin suitable for exclusion of atmosphere and particularly carbon dioxide. A number of other materials are known for their fire resistant quality whether inherently combustion resistant or acquisitive of fire resistance characteristics through particular structural layering or assembly characteristics.